Copper-catalyzed asymmetric sulfoxidation of aryl benzyl and aryl alkyl sulfides, using aqueous hydrogen peroxide as the oxidant, has been investigated. A relationship between the steric effects of the sulfide substituents and the enantioselectivity of the oxidation has been observed, with up to 93% ee for 2-naphthylmethyl phenyl sulfoxide, in modest yield in this instance (up to 30%). The influence
The oxidation of highly branched penyl-alkyl and di-alkyl sulphoxides shows that in the alkaline oxidation steric hindrance has a more pronounced influence than in acidic oxidation, even if the steric effects are not very large. On the basis of these and previous results some suggestions on the geometry of the transition state of the alkaline oxidation are advanced.